The present invention relates to a structure of a box container for sheet bodies or, more particularly, to a novel structure of a box container useful for conservation and transportation of a plural number of precision-worked sheet-like bodies such as lead frames for semiconductor devices such as ICs.
Lead frames used for semiconductor devices and the like are prepared from a sheet of a metal by punching or etching and, when a plural number thereof are to be conserved or transported, they are stacked one on the other and wrapped together with a sheet of wrapping paper or put together into a plastic-made box container.
The above mentioned methods for the conservation and transportation of lead frames are no longer practical in view of the recent development of the devices such as ICs toward higher and higher degree of integration because the lead wire terminals thereof must be extremely fine and delicate. Namely, wrapping of frames with a paper sheet necessarily damages the extremely fine structure as a matter of course. When the lead frames are to be contained in a plastic-made box container, the play, i.e. a space for unimpeded movement of the lead frames within the container, cannot be too small because a too small play means a decreased working efficiency in putting and taking the lead frames into and out of the box container to increase the risk of deformation or damage of the lead frames unless an utmost care is taken although jolting of the lead flames during transportation can be decreased thereby and, when the play is too large, jolting of the lead frames during transportation is increased eventually resulting in the deformation of the lead wire terminals or contamination thereof by rubbing at the walls of the box container although the working efficiency can be improved in putting and taking the lead flames into and out of the box container.